One-chip wonders

Consumer demand for portable computing and mobile wireless communications will continue to drive development of functionally integrated, ultra-low-power systems on a chip. CMOS bulk processing is likely to emerge as the foundation of mixed-signal, ultra-low-power ICs because of its inherent advantages for low-power logic and flexibility in RF applications. To successfully meet time-to-market goals and shrink product-development cycles, computer-aided design tools must guide a design from conceptualization to physical implementation. Estimates of floorplan arrangement and interconnect and package parasitics are necessary early in the design flow, since these undesirable contributions can dominate over the intrinsic device parasitics     

Design of 4-element microstrip array of wideband reflector antenna with stable high gain characteristics

In this paper, three microstrip antennas with and without reflector are proposed with stable and high gain characteristics. The proposed antennas are simple to design and do not involve loading of any active elements on the patch or ground plane. The designed antennas cover the total frequency range of 10.5–44.5 GHz and operate well within the 5G communication frequency band of 27–30 GHz; consequently, making proposed antennas suitable for upcoming wireless technology. Furthermore, a 2 × 2 antenna array with phase diversity is proposed which offers an almost stable gain of about 14 dBi within the operating band. The proposed antennas are analyzed by finite element method based Ansys HFSS simulator. The fabricated prototypes of the optimized designs are made and simulated results are found in good agreement with the measured results.

     

Remote sensing of alpine treeline ecotone dynamics and phenology in Arunachal Pradesh Himalaya

Global warming is inducing the elevational alpine treeline ecotone (ATE) to migrate to higher elevations in the Himalaya. Prior research on ATE dynamics has been primarily based on field inventory and studied at the community level. The potential of using remote sensing and geographic information system for the delineation of the treeline ecotone has been explored. In this study, we used satellite-derived Normalized Difference Vegetation Index (NDVI) data from Landsat-1/2 Multispectral Scanner (MSS), Resourcesat-1/2 Linear Imaging Self Scanning Sensor (LISS-III), and National Oceanographic and Atmospheric Administration-Advanced Very High-Resolution Radiometer (NOAA-AVHRR) to investigate long-term ATE dynamics. Satellite remote sensing of treeline in Arunachal Pradesh Himalaya revealed an upward shift over the past four decades. The ATE has shifted c. 452 m ± 74 m upward in vertical dimension at a rate c. 113 m decade^?1. Furthermore, the land surface phenology along ATE and forest area has changed significantly over the past 33 years. The significant positive trend in length of the growing season (LOS; p < 0.05) and delay in the end of the growing season (EOS) was observed. The start of the growing season (SOS) had a negative tendency with non-significant linear trend. The treeline upward shift and significant lengthening of the growing season at ATE and forest area indicate changing climatic patterns and processes.     

Broad-spectrum antimicrobial activity of bacterial cellulose silver nanocomposites with sustained release

Bacterial cellulose-based antifouling materials have been produced by incorporation of silver nanoparticles for broad-spectrum antimicrobial activity. Three variations of silver nitrate (AgNO₃) to reducing agent concentrations have been tried to vary the silver nanoparticle dimension. The formation of silver nanoparticles was also evidenced by the X-ray diffraction, and the crystallite size was found to decrease with increase in NaBH₄ concentration. AgBC composites having < 2% (W/W) of silver exhibited 99.9% antimicrobial activity which was sustained up to 72 h against spoiled food derived mixed microbial culture. On the other hand, only 90% activity was observed with colloidal AgNPs due to aggregate formation. Composites displayed superior antimicrobial activity than colloid with equivalent amount of silver. Food stuff was protected from microbial spoilage for 30 days when stored in AgBC nanocomposites, whereas spoilage was noticed within 15 days for food stuff stored in regular polythene bag. Therefore, the AgBC composite having < 2% silver can be used as a lining of regular food packaging material to extend shelf life till 30 days. Toxicity due to high amount of silver can be prevented with these composites and can be safely used in healthcare applications such as food packaging, wound dressing, hospital bed lining and surgical apparels.     

Adaptive neuro fuzzy based hybrid force/position control for an industrial robot manipulator

In this paper an ANFIS-PD+I (AFSPD+I) based hybrid force/position controller has been proposed which works effectively with unspecified robot dynamics in the presence of external disturbances. A constraint is put to limit the movement of manipulator in XY Cartesian coordinates. The validity of the proposed controller has been tested using a 6-degree of freedom PUMA robot manipulator. The performance comparison have been done with the fuzzy proportional derivative plus integral, fuzzy proportional integral derivative and conventional proportional integral derivative controllers subjected to the same data set with proposed controller. The projected AFSPD+I controller adhered to the desired path closer and smoother than the other mentioned controllers.     

Implementation of slow wave characteristics in a microstrip antenna and its implementation with substrate integrated waveguide

In this article, a planar slow wave long‐wire‐antenna (LWA) is proposed for RF and microwave applications. Mathematical design equations of transformation of cylindrical LWA into planar microstrip antenna are presented. Slow wave effect produced by LWA is demonstrated in terms of group delay in a square slot aperture antenna and the same is compared with the proposed LWA embedded with square slot in the ground plane. Furthermore, substrate integrated waveguide is embedded with the proposed structure which further enhance the antenna gain and group delay. Group delay of about 2 ns is enhanced to the value of 26.7 ns after the integration of substrate integrated waveguide with LWA. Finite element method is used to investigate the design through Ansoft HFSS simulator, which is further validated by measured results of fabricated prototype.     

CPW-fed triple high rejection notched UWB and X-band antenna on silicon for imaging and wireless applications

In this article, compact coplanar waveguide feed antenna covering ultra-wideband and X-band signals (2.98–13.34 GHz) is presented. Antenna also offers triple-notched band elimination (Wireless Interoperability for Microwave Access: 3.40–3.95 GHz, Wireless Local Area Network: 4.50–6.34 GHz and Downlink Satellite System: 7.11–7.802 GHz) which is due to insertion of stub and etching of slots. Antenna is fabricated and characterised on silicon for imaging and wireless applications having a fractional bandwidth of 133%. The antenna offers gain, radiation efficiency and group delay between 3.26 and 8.00 dBi, 84% and 92% and ≤±1.0 ns, respectively, for the entire bandwidth. Isolation of antenna in face-to-face and side-to-side orientations is <?25 dB with very less distortion presented in the transmission and reception of the signal. The radiations emitted by the antenna are observed as a dipole-like pattern in E-plane and omnidirectional in H-plane.     

A Hybrid SEM-Neural Network Model for Predicting Determinants of Mobile Payment Services

ABSTRACT

This study develops a new research model to understand and predict the key determinants influencing the adoption of mobile payment services in a Middle Eastern country, Oman. The research model was tested using a hybrid structural equation modeling (SEM) and neural network (NN) modeling. The findings suggest valuable insights into the mobile payment service providers in the development of an appropriate and effective strategy to raise the number of new consumers in Oman.